Fixed #36926 -- Made admin use boolean icons for related BooleanFields in list_display.

When using related field lookups like 'parent__is_active' in list_display,
the admin now correctly detects if the final field is a BooleanField and
displays boolean icons instead of 'True'/'False' text.

Modified lookup_field() in django/contrib/admin/utils.py to retrieve the
final field from the path when traversing relations using LOOKUP_SEP (__),
allowing display_for_field() to properly handle BooleanFields.

2 files changed, 30 insertions, 0 deletions

diff --git a/tests/admin_changelist/models.py b/tests/admin_changelist/models.py
index 0b594300d2..d5d0633122 100644
--- a/tests/admin_changelist/models.py
+++ b/tests/admin_changelist/models.py
@@ -17,6 +17,7 @@ class Child(models.Model):
     parent = models.ForeignKey(Parent, models.SET_NULL, editable=False, null=True)
     name = models.CharField(max_length=30, blank=True)
     age = models.IntegerField(null=True, blank=True)
+    is_active = models.BooleanField(default=True)
 
 
 class GrandChild(models.Model):
diff --git a/tests/admin_changelist/tests.py b/tests/admin_changelist/tests.py
index f051849449..ef0f8a0570 100644
--- a/tests/admin_changelist/tests.py
+++ b/tests/admin_changelist/tests.py
@@ -1768,6 +1768,35 @@ class ChangeListTests(TestCase):
         cl = m.get_changelist_instance(request)
         self.assertEqual(cl.get_ordering_field_columns(), {2: "asc"})
 
+    def test_list_display_related_field_boolean_display(self):
+        """
+        Related boolean fields (parent__is_active) display boolean icons.
+        """
+        parent = Parent.objects.create(name="Test Parent")
+        child_active = Child.objects.create(
+            name="Active Child", parent=parent, is_active=True
+        )
+        child_inactive = Child.objects.create(
+            name="Inactive Child", parent=parent, is_active=False
+        )
+
+        class GrandChildAdmin(admin.ModelAdmin):
+            list_display = ["name", "parent__is_active"]
+
+        GrandChild.objects.create(name="GrandChild of Active", parent=child_active)
+        GrandChild.objects.create(name="GrandChild of Inactive", parent=child_inactive)
+
+        m = GrandChildAdmin(GrandChild, custom_site)
+        request = self._mocked_authenticated_request("/grandchild/", self.superuser)
+        response = m.changelist_view(request)
+
+        # Boolean icons are rendered using img tags with specific alt text.
+        self.assertContains(response, 'alt="True"')
+        self.assertContains(response, 'alt="False"')
+        # Ensure "True" and "False" text are NOT in the response.
+        self.assertNotContains(response, ">True<")
+        self.assertNotContains(response, ">False<")
+
 
 class GetAdminLogTests(TestCase):
     def test_custom_user_pk_not_named_id(self):